This invention relates to the infrared non-destructive testing of targets and more particularly, to a method and apparatus for the thermal examination of a target by selective sampling utilizing an infrared fiber optic radiometer.
Infrared scanners have been utilized for non-destructively destructively thermally testing a variety of products and uses, such as machines, printed circuits, chips, microcircuits, process control, etc. However, many of the infrared scanners are research type instruments which have predetermined scanning patterns for monitoring predetermined areas of the product and therefor are too slow for on line inspecting of mass production items. However, for such purposes it is not always necessary to thermally survey the entire area or every point on a product, circuit, or device. In many cases the selection of a few significant elements for thermally sensitive areas for example, 5-20 may be all that is required. Any apparatus utilized for such a purpose must have the capability of selectively changing the significant areas to be examined without substantially structurally changing the infrared radiometer which is being utilized for the examination otherwise a new instrument would have to be used whenever the selection of desired areas is changed or single individual measurements would have to be made for each of the points of interest.